The only real unique thing about the military CUCV Blazer is that it came with a TH400 transmission and the hybrid 24/12 volt electrical system. Otherwise it is just a stripped own civvy version. Personally I think the TH700R4 and lower axle gears makes for a much better combination (I have a '90 that came with the 700 and 3.73).
Regarding the whole 3/4 ton Blazer and 5/4 ton truck.......find me a factory or dealer document from this era that actually states "1/2 ton", "3/4 ton", etc... Maybe they exist but everything I have seen states something like K10, C20, etc... All of that is just old school slang terms that people still use to distinguish different levels of trucks but it's not accurate. My 2500HD that everybody calls a "3/4 ton" has a GVW of 9,200 lbs. but only ways about 6,500 lbs. empty so techically it should be well over a 1 ton. New "1/2 tons" have a payload over 3/4 tons, etc... So nothing special about the payload capacity of the CUCV trucks, just that the military rated them for what they actually could carry vs. using some old slang terms.